NATO reported only light resistance in Arghandab district, a lush river valley filled with fruit groves that offer militants bountiful defensive positions. The Afghan army says up to 400 militants poured into the area on Monday, just 10 miles northwest of Kandahar city, the Taliban's former power base.

U.S. and NATO officials have repeatedly played down the scope of the Taliban push. But the swift military response - 700 Afghan soldiers flew to Kandahar on a moment's notice - and the fighter aircraft dedicated by NATO suggest that keeping Arghandab free from militants is an urgent priority.

Arghandab is considered a gateway to Kandahar. If militants can gain a foothold there, attacks become easier on the city once commanded by fugitive Taliban leader Mullah Omar.

Elsewhere in Afghanistan, militants killed six NATO soldiers and wounded 10. Just last week Defense Secretary Robert Gates called attention to the worsening situation in Afghanistan, noting that American and allied combat deaths here in May surpassed the monthly toll in Iraq for the first time.

The Afghan Defense Ministry said more than 20 Taliban fighters were killed Wednesday in NATO airstrikes in the Arghandab village of Tabin and 16 more were killed in the village of Khohak. Two Afghan soldiers were also killed, the ministry said in a statement.

Twelve other militants were killed in fighting in Maiwand, a separate district also in Kandahar province.

The governor of Kandahar, Asadullah Khalid, said the Taliban had controlled 10 towns in the Arghandab district, but government and NATO forces took back four of them.

Khalid said that "a large number" of Afghans have been displaced by the fighting - other officials estimated thousands had fled. He said officials have requested help from the U.N.